A mathematical approach to cost minimization of satcom systems

A mathematical technique is described that formalizes the process of cost minimization in satcom systems by trading off interrelated parameters. It can be used as an aid to the traditional "spread-sheet" approach to indicate what modifications to parameters will lead to cost reduction, and if cost minimums exist. In the first step, the total life-cycle cost function is described as the sum of interrelated major terms. In turn, each of these consist of many terms. The second step is the determination of cost functions. Then, equations that tie certain of the component items together are determined. Finally, the cost is minimized by varying the component parameters to give the minimum total cost. Symbolic mathematical software is found to greatly ease this analysis. The approach is explained by means of three examples: (1) terminal power and antenna gain, and payload power and antenna gain are tied together with the link equations, (2) terminal reliability and maintainability are related by the availability relation, and (3) spacecraft sparing and reliability are balanced to achieve the specified constellation reliability. The examples show that cost minimums exist and can be determined with potential for considerable savings. The method is straightforward to extend to the entire life-cycle costing.